For a variety of applications it may be desirable to fabricate carbon nanotubes having a controlled length. For example, carbon nanotubes having a controlled length can be desirable for optical materials including opto-mechanical systems, optical barcoding, composites, self-assembled nanotube architectures, bio-medical applications, etc.
Although a great many methods are known and reported for carbon nanotube synthesis, these methods are, in general, not well-suited to the production of carbon nanotubes having well controlled length. In particular, these methods are generally not well-suited to the production (in an economically scalable manner) of relatively short carbon nanotubes having a controlled length.
Furthermore, although various methods have been developed and reported for modifying and/or selecting the length of carbon nanotubes after they are grown, such methods are, in general, not well suited to providing scalable quantities of well-tailored carbon nanotube materials. In the prior art, long nanotubes are cut by mechanical processes such as ball milling (Chem. Phys Lett 335, 2001, 1-8, Pierard), or by chemical processes such as acid etching (either alone or with sonication) (Science, Vol. 280, 22 May 1998, pp 1253-1256) which exploits defects in the nanotubes so as to cleave them. These and other processes known in the art are not sufficiently length-selective, and produce a poorly controlled distribution of nanotube lengths.
Many applications can benefit from better control of nanotube length. Accordingly, a process by which nanotubes can be created having specific lengths would be advantageous. In addition, it can be desirable to produce length-specific open-ended carbon nanotubes and/or carbon nanotubes with functional end moieties (e.g., oxygen-bearing species) which can be utilized to create site-specific functionalization of the length-specific carbon nanotubes.